Buggy code:
public class ExpressionStoreQuery extends AbstractStoreQuery { private static final Localizer _loc = Localizer . forPackage ( ExpressionStoreQuery . class ) ; private static final FilterListener [ ] _listeners = new FilterListener [ ] { new StringContains ( ) , new WildcardMatch ( ) } ; private final ExpressionParser _parser ; private transient Object _parsed ; public ExpressionStoreQuery ( ExpressionParser parser ) { } public Resolver getResolver ( ) { } public boolean setQuery ( Object query ) { } public FilterListener getFilterListener ( String tag ) { } public Object newCompilation ( ) { } public void populateFromCompilation ( Object comp ) { } public void invalidateCompilation ( ) { } public boolean supportsInMemoryExecution ( ) { } public Executor newInMemoryExecutor ( ClassMetaData meta , boolean subs ) { } public Executor newDataStoreExecutor ( ClassMetaData meta , boolean subs ) { } protected ResultObjectProvider executeQuery ( Executor ex , ClassMetaData base , ClassMetaData [ ] types , boolean subclasses , ExpressionFactory [ ] facts , QueryExpressions [ ] parsed , Object [ ] params , boolean lrs , long startIdx , long endIdx ) { } protected Number executeDelete ( Executor ex , ClassMetaData base , ClassMetaData [ ] types , boolean subclasses , ExpressionFactory [ ] facts , QueryExpressions [ ] parsed , Object [ ] params ) { } protected Number executeUpdate ( Executor ex , ClassMetaData base , ClassMetaData [ ] types , boolean subclasses , ExpressionFactory [ ] facts , QueryExpressions [ ] parsed , Object [ ] params ) { } protected String [ ] getDataStoreActions ( Executor ex , ClassMetaData base , ClassMetaData [ ] types , boolean subclasses , ExpressionFactory [ ] facts , QueryExpressions [ ] parsed , Object [ ] params , long startIdx , long endIdx ) { } protected ClassMetaData [ ] getIndependentExpressionCandidates ( ClassMetaData type , boolean subclasses ) { } protected ExpressionFactory getExpressionFactory ( ClassMetaData type ) { } private abstract static class AbstractExpressionExecutor extends AbstractExecutor implements Executor { protected abstract QueryExpressions [ ] getQueryExpressions ( ) { } private QueryExpressions assertQueryExpression ( ) { } protected void assertNotContainer ( Value val , StoreQuery q ) { } public final void validate ( StoreQuery q ) { } public final Class getResultClass ( StoreQuery q ) { } public final boolean [ ] getAscending ( StoreQuery q ) { } public final String getAlias ( StoreQuery q ) { } public final String [ ] getProjectionAliases ( StoreQuery q ) { } public final int getOperation ( StoreQuery q ) { } public final boolean isAggregate ( StoreQuery q ) { <START_BUG> return assertQueryExpression ( ) . aggregate ; <END_BUG> } public final boolean hasGrouping ( StoreQuery q ) { } public final LinkedMap getParameterTypes ( StoreQuery q ) { } public final Map getUpdates ( StoreQuery q ) { } public final ClassMetaData [ ] getAccessPathMetaDatas ( StoreQuery q ) { } public boolean isPacking ( StoreQuery q ) { } private static class ValidateGroupingExpressionVisitor extends AbstractExpressionVisitor { private final QueryContext _ctx ; private boolean _grouping = false ; private Set _grouped = null ; private Value _agg = null ; public static void validate ( QueryContext ctx , QueryExpressions exps ) { } public ValidateGroupingExpressionVisitor ( QueryContext ctx ) { } public void enter ( Value val ) { } public void exit ( Value val ) { } } } private static class InMemoryExecutor extends ExpressionStoreQuery . AbstractExpressionExecutor implements Executor { private final ClassMetaData _meta ; private final boolean _subs ; private final InMemoryExpressionFactory _factory ; private final QueryExpressions [ ] _exps ; private final Class [ ] _projTypes ; public InMemoryExecutor ( ExpressionStoreQuery q , ClassMetaData candidate , boolean subclasses , ExpressionParser parser , Object parsed ) { } protected QueryExpressions [ ] getQueryExpressions ( ) { } public ResultObjectProvider executeQuery ( StoreQuery q , Object [ ] params , boolean lrs , long startIdx , long endIdx ) { } public ResultObjectProvider executeQuery ( StoreQuery q , Map params , boolean lrs , long startIdx , long endIdx ) { } public String [ ] getDataStoreActions ( StoreQuery q , Object [ ] params , long startIdx , long endIdx ) { } public Object getOrderingValue ( StoreQuery q , Object [ ] params , Object resultObject , int orderIndex ) { } public Class [ ] getProjectionTypes ( StoreQuery q ) { } private static class AssertNoVariablesExpressionVisitor extends AbstractExpressionVisitor { private final QueryContext _ctx ; public AssertNoVariablesExpressionVisitor ( QueryContext ctx ) { } public void enter ( Value val ) { } } } private static class DataStoreExecutor extends ExpressionStoreQuery . AbstractExpressionExecutor implements Executor { private final ClassMetaData _meta ; private final ClassMetaData [ ] _metas ; private final boolean _subs ; private final ExpressionParser _parser ; private final ExpressionFactory [ ] _facts ; private final QueryExpressions [ ] _exps ; private Value [ ] _inMemOrdering ; private Class [ ] _projTypes ; public DataStoreExecutor ( ExpressionStoreQuery q , ClassMetaData meta , boolean subclasses , ExpressionParser parser , Object parsed ) { } protected QueryExpressions [ ] getQueryExpressions ( ) { } public ResultObjectProvider executeQuery ( StoreQuery q , Object [ ] params , boolean lrs , long startIdx , long endIdx ) { } public ResultObjectProvider executeQuery ( StoreQuery q , Map params , boolean lrs , long startIdx , long endIdx ) { } public Number executeDelete ( StoreQuery q , Object [ ] params ) { } public Number executeDelete ( StoreQuery q , Map params ) { } public Number executeUpdate ( StoreQuery q , Object [ ] params ) { } public Number executeUpdate ( StoreQuery q , Map params ) { } public String [ ] getDataStoreActions ( StoreQuery q , Object [ ] params , long startIdx , long endIdx ) { } public Object getOrderingValue ( StoreQuery q , Object [ ] params , Object resultObject , int orderIndex ) { } public Class [ ] getProjectionTypes ( StoreQuery q ) { }

Fix:
return assertQueryExpression ( ) . isAggregate ( ) ;